JP4894776B2 - Battery monitoring device - Google Patents

Description

  The present invention provides a high-potential side connection means between the unit battery and the capacitor so as to detect each voltage of the unit battery composed of one or a plurality of adjacent battery cells constituting an assembled battery as a series connection body of battery cells. After the voltage of the unit cell is applied to the capacitor by electrically connecting the unit, the connection is released, and the unit is electrically connected between the capacitor and the voltage detecting unit by a low-potential side connecting unit. The present invention relates to a battery pack monitoring device that detects battery voltage.

  FIG. 8A illustrates the configuration of this type of monitoring device. The illustrated assembled battery 10 is a series connection body of battery cells B0 to B3, and the negative electrode of each of the battery cells Bi (i = 0 to 3) can be connected to the flying capacitor 12 via the switching element SWi. The positive electrode of the battery cell Bi can be connected to the flying capacitor via the switching element SW (i + 1). The flying capacitor 12 can be connected to the voltage detection circuit 14 via the switching elements SSa and SSb. In such a configuration, for example, after the switching elements SW0 and SW1 are turned on to apply the voltage of the battery cell B0 to the flying capacitor 12, the switching elements SW0 and SW1 are turned off, and the switching elements SSa and SSb are turned on. By setting the state, the voltage detection circuit 14 can detect the voltage of the battery cell B0.

  FIG. 9A illustrates a case where two flying capacitors 12a and 12b and voltage detection circuits 14a and 14b are provided so that the voltages of two battery cells can be detected at a time.

In addition, as such an assembled battery monitoring device, for example, there is a device found in Patent Document 1 below.
JP 2002-281682 A

  By the way, when an abnormality (short circuit) occurs in any of the switching elements SW0 to SW4, the voltage applied to the flying capacitors 12, 12a and 12b is different from the voltage of the selected battery cell. As a result, the voltage cannot be detected properly. FIG. 8B shows detected voltages V0 to V3 of the battery cells B0 to B3 when the switching elements SW0 to SW4 are short-circuited in the configuration of FIG. 8A. Here, the actual voltages of the battery cells B0 to B3 are all “10”. FIG. 9B shows detected voltages V0 to V3 of the battery cells B0 to B3 when the switching elements SW0 to SW4 are short-circuited in the configuration of FIG. 9A.

  As described above, when any of the switching elements SW0 to SW4 is short-circuited, the voltage of the battery cell cannot be detected appropriately.

  On the other hand, the voltages of the battery cells B0 to B3 can also vary depending on the presence or absence of abnormality of the battery cells B0 to B3 itself such as the state of charge thereof. For this reason, depending on the detected voltage values V0 to V3 of the battery cells B0 to B3, there is a concern that it may not be possible to specify whether the switching elements SW0 to SW4 are abnormal or the battery cells B0 to B4 themselves are abnormal. In particular, the result shown in FIG. 9B is generally detected by a single voltage detection circuit, as can be seen from the fact that the degree of abnormality is lower than the result shown in FIG. 8B. The smaller the number of target battery cells, the more difficult the above identification.

  The present invention has been made in order to solve the above-mentioned problems, and the object thereof is between a unit battery and a power storage means, each of which is composed of one or a plurality of adjacent battery cells constituting an assembled battery as a series connection body of battery cells. To provide a battery pack monitoring device that can more accurately determine whether or not there is an abnormality in at least one of a high potential side connecting means for connecting the battery and a low potential side connecting means for connecting between the power storage means and the voltage detecting means. It is in.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  According to the first aspect of the present invention, in order to detect each voltage of a unit battery composed of one or a plurality of adjacent battery cells constituting an assembled battery as a series connection body of battery cells, the unit is connected by a high potential side connection means. After the voltage of the unit battery is applied to the power storage means by electrically connecting the battery and the power storage means, the connection is released, and the power storage means and the voltage detection means are electrically connected by the low potential side connection means. In the assembled battery monitoring device that detects the voltage of the unit battery by connecting to the alternating current signal output means, an output terminal is electrically connected to the assembled battery via a capacitor and a resistor, and the alternating current signal output The resistor and the resistor in a period in which an AC signal is output by the means and the electrical connection is made by either the low potential side connection means or the high potential side connection means. Based on the voltage across the capacitor, wherein the comprises a determination unit configured to determine either the presence or absence of other abnormal low-potential-side connecting unit and the high-potential-side connecting means.

  When an AC signal is output by the AC signal output means, the voltage between the capacitor and the resistor varies according to the voltage variation of the AC signal. On the other hand, the resistance between the electrical path including the low potential side connection means and the voltage detection means and the ground tends to be lower than the normal insulation level. However, even if the electrical connection is made by either one of the low potential side connection means and the high potential side connection means, if the electrical connection by either one is not made, the capacitor and the resistor The voltage fluctuation state between them does not change. However, in the case where an abnormality that causes the insulation failure occurs in either of the other, the electrical connection by either one is performed, and the above-described electric path including the low potential side connection unit and the voltage detection unit is used. The connection between the resistor and the capacitor is brought into a conductive state, and the electric system from the resistor and the capacitor to the ground through the electric path is brought into a conductive state. As a result, the voltage between the capacitor and the resistor when the AC signal is output from the AC signal output means decreases. In the above invention, by paying attention to this point, it is possible to accurately determine the other abnormality (insulation failure abnormality).

  According to a second aspect of the present invention, in the first aspect of the invention, the high potential side connection means is a multiplexer that allows one of the unit cells to be selected and electrically connected to the power storage means. It is characterized by that.

  In the above invention, since the high-potential side connection means is a multiplexer, when there is an abnormality in insulation failure in the means for electrically connecting a specific unit cell of the plurality of unit batteries to the power storage means, Due to this influence, the voltage of other unit batteries may not be detected properly. However, it is difficult to specify whether the abnormality of the voltage value is caused by the abnormality of the multiplexer or the abnormality of the battery cell itself. In this regard, in the above-described invention, the abnormality of the multiplexer can be accurately determined by providing the determination means.

According to a third aspect of the present invention, in the first or second aspect of the invention, the electrical connection time for determination processing by the determination unit according to any one of the low potential side connection unit and the high potential side connection unit. Is further set longer than the electrical connection time by the high potential side connection means at the time of voltage detection of the unit battery, and the determination means has the connection time set by the setting means In this case, the determination is performed.

  The phenomenon that the peak value of the AC signal appearing between the capacitor and the resistor decreases due to the occurrence of insulation failure in the electric path including the low potential side connection means and the voltage detection means is that the capacitor is sufficiently charged. Prominently occurs. On the other hand, the capacitor generally tends to have a larger capacity than the power storage means. For this reason, in order to secure the charging time of the capacitor, the connection time of either the low potential side connection means or the high potential side connection means is used when the voltage is applied to the power storage means for voltage detection of the unit battery. It is desirable to make it longer than the connection time by the high potential side connection means. In the above invention, in view of this point, by providing the setting means, it is possible to determine the presence or absence of abnormality after a lapse of time when it is assumed that the capacitor is sufficiently charged, thereby improving the determination accuracy. Can do.

  The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the assembled battery is mounted on a vehicle, and an AC signal is output by the AC signal output means. And a vehicle body and a high-voltage system including the assembled battery based on a voltage between the resistor and the capacitor during a period when the electrical connection is not performed by any of the low potential side connection means and the high potential side connection means. Insulation failure detection means for detecting the presence or absence of insulation failure is further provided.

  When an AC signal is output by the AC signal output means, the voltage between the capacitor and the resistor varies according to the voltage variation of the AC signal. Here, when the high-voltage system including the assembled battery and the vehicle body are poorly insulated, the electrical system from the resistor and the capacitor to the ground via the high-voltage system becomes conductive. As a result, the voltage between the capacitor and the resistor when the AC signal is output from the AC signal output means decreases. In the above invention, by paying attention to this point, it is possible to appropriately detect the presence or absence of insulation failure between the vehicle body and the high-pressure system. In particular, since this detection process is partially the same as the above-described determination process, the determination unit and the insulation failure detection unit can share a part of their constituent elements with each other and the AC signal output unit. Can also share this.

  According to a fifth aspect of the present invention, in the fourth aspect of the invention, the determination unit performs the determination based on whether or not an insulation failure is detected by the insulation failure detection unit.

  When an insulation failure is detected by the insulation failure detection means, an AC signal is output and any one of the above even if there is no abnormality in either the low potential side connection means or the high potential side connection means. Abnormality may occur in the voltage between the resistor and the capacitor during the period in which electrical connection is made by one side. In the above invention, in view of this point, the abnormality due to the insulation failure between the high-pressure system and the vehicle body is determined by determining the presence or absence of the other abnormality based on the presence or absence of the insulation failure detected by the insulation failure detection means. It is possible to avoid misjudging one of the other abnormalities.

The invention according to claim 6 is the invention according to any one of claims 1 to 5, further comprising a ground fault means for grounding between the low potential side connection means and the voltage detection means, the judgment means. Is characterized in that the determination is performed when the ground fault means has a ground fault between the low voltage side connection means and the voltage detection means.

  The degree to which the voltage between the resistor and the capacitor at the time of output of the AC signal changes according to the presence or absence of abnormality of the other connection means is determined by the electrical path including the low potential side connection means and the voltage detection means, and grounding. Depends on the resistance value. The degree of the change becomes smaller as the resistance value is larger. In this regard, in the above invention, by providing the ground fault means, the resistance value between the low potential side connection means and the voltage detection means and the ground can be suitably reduced, and as a result, the resistance at the time of output of the AC signal can be reduced. The voltage between the body and the capacitor can be greatly changed according to the presence or absence of an abnormality in the other connection means.

(First embodiment)
Hereinafter, a first embodiment in which an assembled battery monitoring device according to the present invention is applied to a hybrid vehicle will be described with reference to the drawings.

  FIG. 1 shows the system configuration of this embodiment. The illustrated assembled battery 10 constitutes a vehicle-mounted high-voltage battery, supplies power to the vehicle-mounted rotating machine, charges electric energy supplied from the vehicle-mounted rotating machine, and further includes a step-down converter (not illustrated). Power is supplied to the vehicle-mounted low-voltage battery. The assembled battery 10 is a series connection body of battery cells B0 to B3. Here, the battery cell Bi (i = 0 to 3) is a lithium secondary battery. In FIG. 1, the assembled battery 10 is schematically illustrated as a series connection body of four battery cells B0 to B3, but actually, a desired high voltage (for example, “288V”) is realized. Therefore, the assembled battery 10 is composed of a series connection body of several tens of battery cells Bi.

  A wiring Li is connected to the negative terminal of each battery cell Bi constituting the assembled battery 10, and a wiring L (i + 1) is connected to the positive terminal of each battery cell Bi. Each wiring Lj (j = 0 to 4) includes a resistor 11 and is connected to the multiplexer MPX at the other end of the resistor 11.

  The multiplexer MPX selectively connects a pair of wirings Li and L (i + 1) to the flying capacitor 12. Specifically, the multiplexer MPX connects the pair of wirings Li and L (i + 1) to the flying capacitor 12 in such a manner that the charging polarities when the voltages of adjacent battery cells are applied to the flying capacitor 12 are opposite to each other. The multiplexer MPX includes a switching element SWj corresponding to each wiring Lj, and the switching elements SW0, SW2, SW4 and the switching elements SW1, SW3 are connected to different electrodes of the flying capacitor 12. . Note that the switching elements SW0 to SW4 are configured by an insulating element such as a photo MOS relay, for example.

  The flying capacitor 12 can be connected to the voltage detection circuit 14 via the switching elements SSa and SSb. The flying capacitor 12 is electrically connected to the voltage detection circuit 14, so that the voltage of the flying capacitor 12 is detected by the voltage detection circuit 14. Here, in the present embodiment, as the voltage detection circuit 14, a differential amplifier circuit configured by an operational amplifier is illustrated. In the drawing, it is described that the inverting input terminal of the operational amplifier constituting the voltage detection circuit 14 and the ground are electrically connected by the resistor 16. The combined impedance between the actual electrical system including SSa, SSb and the voltage detection circuit 14 and the ground is schematically shown. The switching elements SSa and SSb are composed of insulating elements such as photo MOS relays.

  The output signal of the voltage detection circuit 14 is taken into an assembled battery electronic control device (battery ECU 20). The battery ECU 20 includes an analog-digital conversion device (A / D conversion device 22), which converts the output voltage of the voltage detection circuit 14 into digital data. The control unit 24 performs various digital processes based on the digital data output from the A / D conversion device 22.

  Further, the control unit 24 detects the voltage of the battery cell Bi by operating the multiplexer MPX and the switching elements SSa and SSb. That is, when detecting the voltage of the battery cell Bi, the switching elements SSa and SSb are turned off, and the switching elements SWi and SW (i + 1) are turned on for a predetermined time Ta (for example, “several ms”). Thus, the voltage of the battery cell Bi is applied to the flying capacitor 12. Then, after the battery cell Bi and the flying capacitor 12 are insulated, the switching elements SSa and SSb are turned on to apply the voltage of the flying capacitor 12 to the voltage detection circuit 14. Thus, the battery ECU 20 can detect the voltage of each battery cell Bi.

  Further, the battery ECU 20 performs processing for detecting the presence or absence of insulation failure between the vehicle-mounted high-voltage system including the assembled battery 10 and the vehicle body. This is a process corresponding to the regulation that the high pressure system must be insulated from the vehicle body. The ground line for the battery ECU 20 is the vehicle body.

  In order to execute such processing, the control unit 24 outputs a rectangular wave AC signal (rectangular wave signal RS). The rectangular wave signal RS is taken into the voltage follower 26 as impedance conversion means. The output of the voltage follower 26 is electrically connected to the assembled battery 10 via the resistor 28 and the capacitor 38. Specifically, in this embodiment, the battery pack 10 is connected to the wiring L0 on the negative electrode side of the battery pack 10. On the other hand, the connection point between the resistor 28 and the capacitor 38 is applied to the inverting input terminal of the comparator 30, and the threshold voltage Vth is applied to the non-inverting input terminal of the comparator 30. Here, the threshold voltage Vth is generated by dividing the voltage of the power supply 32 by the resistors 34 and 36. The output of the comparator 30 is taken into the control unit 24. In the control unit 24, when the switching elements SW0 to SW4 and the switching elements SSa and SSb are in an off state, the controller 24 determines whether or not there is an insulation failure between the high-voltage system and the vehicle body based on the output of the comparator 30 when the rectangular wave signal RS is output. to decide.

  That is, when the insulation between the high-voltage system and the vehicle body is good, the control unit 24 outputs the voltage Va applied to the inverting input terminal of the comparator 30, in other words, the voltage Va between the resistor 28 and the capacitor 38. The rectangular wave signal RS itself. On the other hand, when the insulation between the high voltage system and the vehicle body is insufficient, a closed loop circuit including the vehicle body, the resistor 28, the capacitor 38, and the high voltage system is formed. The voltage Va decreases. Therefore, by setting the threshold voltage Vth to a value that can determine the change of the voltage Va due to the presence or absence of these insulation failures, it is possible to determine the presence or absence of insulation failures between the high-voltage system and the vehicle body.

  By the way, when the switching elements SW0 to SW4 constituting the multiplexer MPX are turned off, an abnormality may occur in which they are in an electrically conductive state. In this case, the voltage of the battery cell Bi constituting the assembled battery 10 cannot be detected appropriately as described above.

  Therefore, in the present embodiment, the presence or absence of insulation failure of the switching elements SW0 to SW4 is determined using the hardware used to determine the presence or absence of insulation failure between the high-voltage system and the vehicle body. This can be performed based on the voltage Va between the resistor 28 and the capacitor 38 when the rectangular wave signal RS is output when the switching elements SSa and SSb are on. FIG. 2 shows a method for determining whether or not the switching elements SW0 to SW4 have an insulation failure.

  FIG. 2A shows a normal case where the switching elements SW0 to SW4 are normal. As illustrated, in this case, the rectangular wave signal RS is applied to the resistor 28, so that the voltage Va between the resistor 28 and the capacitor 38 becomes an AC signal corresponding to the rectangular wave signal RS, and The peak value exceeds the threshold voltage Vth. This is because the resistance value R1 (for example, several hundred kΩ) of the resistor 28 is negligibly small compared to the resistance (for example, several tens of MΩ) between the high-voltage system and the vehicle body.

  On the other hand, as illustrated in FIG. 2B, when the switching element SW1 has poor insulation, the resistor 28, the capacitor 38, the switching element SW1, the switching element SSb, the resistor 16 and the vehicle body are connected. A closed loop circuit is formed. Therefore, the voltage between the resistor 28 and the capacitor 38 is obtained by dividing the voltage of the rectangular wave signal RS output from the control unit 24 by the resistor 28 and the resistor 16. Here, since the resistance value R3 (for example, several hundred kΩ) of the resistor 16 is approximately the same as the resistance value R1 of the resistor 28, the voltage Va between the resistor 28 and the capacitor 38 is compared with that in the normal state. Get smaller. For this reason, the threshold voltage Vth is not exceeded. In the above discussion, the resistance value of the resistor 11 is negligible compared to that of the resistors 28 and 16.

  FIG. 3 shows a procedure for determining whether or not there is an abnormality in the switching elements SW0 to SW4 according to the present embodiment. This process is repeatedly executed by the control unit 24 at a predetermined cycle, for example.

In this series of processing, first, in step S10, it is determined whether or not an abnormality diagnosis execution condition is satisfied. Here, the abnormality diagnosis execution condition may be any of the following, for example.
a. Conditions immediately after the main power supply of the in-vehicle control device is turned on: Here, the in-vehicle control device is preferably a control device that controls the in-vehicle power generation device. Here, the main power source is turned on when, for example, the means for allowing the user to recognize himself / herself is brought close to the vehicle, or the user operates the portable operation means to output a command signal that is turned on. Etc.
b. When a predetermined time elapses: If abnormality diagnosis is executed at a predetermined cycle, abnormalities in the switching elements SW0 to SW4 can be detected early.
c. Immediately after the main power supply of the in-vehicle control device is turned off: Again, the in-vehicle control device is preferably a control device that controls the in-vehicle power generation device. Here, the main power supply is turned off because, for example, a command signal that causes the user to recognize himself / herself is more than a predetermined distance from the vehicle, or that the user operates the portable operating means to enter the off state. This is the case when outputting.
d. Stopping power supply to the power conversion circuit: The assembled battery is connected to a rotating machine as an in-vehicle power generation device via a power conversion circuit (inverter). Here, between the battery pack and the power conversion circuit, conduction control means such as a relay for electrically conducting and blocking between them is provided. The condition is that the battery pack and the power conversion circuit are disconnected by the conduction control means. Note that these instructions for conduction are normally performed by the user operating the in-vehicle operation unit.

  If it is determined that the abnormality diagnosis execution condition is satisfied, in step S12, the switching elements SSa and SSb are turned on, and the rectangular wave signal RS is output. When the process of step S12 is completed, the process waits for a predetermined time T (step S14). This is because until the capacitor 38 is charged, the behavior of the voltage Va between the resistor 28 and the capacitor 38 does not accurately reflect the presence / absence of the abnormality of the switching elements SW0 to SW4. Here, the predetermined time T is a time (for example, “several hundred ms”) longer than the predetermined time Ta for turning on the switching elements SWi and SW (i + 1) when the voltage of the battery cell Bi is detected. This is because the capacitance of the capacitor 38 is larger than the capacitance of the flying capacitor 12. For this reason, the time required to assume that the behavior of the voltage Va between the resistor 28 and the capacitor 38 accurately reflects the presence or absence of abnormality of the switching elements SW0 to SW4 is the time for detecting the voltage of the battery cell Bi. Longer than scale. Incidentally, the period TP of the rectangular wave signal RS is also set to a time (for example, “several hundred ms”) longer than a predetermined time Ta for turning on the switching elements SWi and SW (i + 1) during voltage detection.

  When the predetermined time T has elapsed, it is determined in step S16 whether or not the voltage Va between the resistor 28 and the capacitor 38 is greater than the threshold voltage Vth. More precisely, it is determined whether or not it periodically becomes larger than the threshold voltage Vth. If it is determined that it is large, it is determined in step S18 that the switching elements SW0 to SW4 are normal. On the other hand, if it is determined that the voltage is equal to or lower than the threshold voltage, it is determined in step S20 that the switching elements SW0 to SW4 are abnormal.

  Thus, in this embodiment, the presence or absence of abnormality of the switching elements SW0 to SW4 can be appropriately determined by diverting hardware means for detecting the presence or absence of insulation failure between the high-pressure system and the vehicle body. . For this reason, when the voltage detection result is abnormal, it is possible to specify whether the abnormality is caused by the battery cell Bi itself or the abnormality of the switching elements SW0 to SW4. Therefore, the fail-safe process at the time of abnormality can be a process based on the assumption that an abnormality has occurred in the multiplexer MPX. In addition, when replacing parts, since an abnormal part is specified, it is not necessary to replace an unnecessarily large number of parts. On the other hand, as shown in FIGS. 8 and 9, it may not be possible to specify whether the battery cell Bi is abnormal or the multiplexer MPX is abnormal only from the abnormality of the voltage detection result. Even as a safe process, an excessive process based on both abnormalities must be performed. Furthermore, there is a risk that excessive component replacement may be performed during component replacement.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) Based on the voltage between the resistor 28 and the capacitor 38 during the period when the rectangular wave signal RS is output and the electrical connection between the flying capacitor 12 and the voltage detection circuit 14 is made by the switching elements SSa and SSb, The presence or absence of abnormality of the switching elements SW0 to SW4 was determined. Thereby, the presence or absence of an insulation failure abnormality of the switching elements SW0 to SW4 can be accurately determined.

  (2) The switching elements SW <b> 0 to SW <b> 4 are multiplexers MPX that select any one of the plurality of battery cells B <b> 0 to B <b> 3 and can be electrically connected to the flying capacitor 12. In this case, when the switching elements SW0 to SW4 are abnormal, the voltage of the battery cell Bi may not be detected properly. However, it is difficult to specify whether the abnormality of the voltage value is caused by the abnormality of the multiplexer MPX or the abnormality of the battery cell Bi itself. For this reason, the utility value of this invention is especially high.

  (3) When determining whether or not there is an abnormality in the switching elements SW0 to SW4, the ON time (predetermined time T) of the switching elements SSa and SSb is set to a predetermined value for turning on the switching elements SW0 to SW4 when the voltage of the battery cell Bi is detected It was longer than time Ta. As a result, it is possible to determine the presence or absence of abnormality after a lapse of time when it is assumed that the capacitor 38 is sufficiently charged, thereby improving the determination accuracy.

  (4) Based on the voltage Va between the resistor 28 and the capacitor 38 during the period in which the rectangular wave signal RS is output and the switching elements SSa and SSb and the switching elements SW0 to SW4 are all in the off state, By using the means for detecting the presence or absence of insulation failure, the presence or absence of abnormality in the switching elements SW0 to SW4 was determined. Thereby, in order to judge the presence or absence of abnormality of switching element SW0-SW4, the number of parts newly added can be reduced.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, it is determined whether or not the switching elements SSa and SSb are abnormal. FIG. 4 shows a procedure for determining whether there is an abnormality according to the present embodiment. This process is repeatedly executed by the control unit 24 at a predetermined cycle, for example. In FIG. 4, processes corresponding to the processes shown in FIG. 3 are given the same reference numerals for convenience.

  In this series of processing, when it is determined in step S10 that the abnormality diagnosis execution condition is satisfied, the switching elements SW0 to SW4 are turned on in step S12a. Then, according to the determination result in the process of step S16, the determination that the switching elements SSa and SSb are normal (step S18a) or the switching elements SSa and SSb are abnormal in the manner of the process of FIG. A determination to that effect is made (step S20a).

  According to the present embodiment described above, it is possible to obtain an effect according to the effects (1), (3), and (4) of the previous first embodiment.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  In the present embodiment, determination of the presence / absence of abnormality of the switching elements SW0 to SW4 based on the detection result of the presence or absence of insulation failure by outputting the rectangular wave signal RS in the off state of the switching elements SW0 to SW4 and the switching elements SSa and SSb. I do.

  FIG. 5 shows a procedure for determining whether there is an abnormality according to the present embodiment. This process is repeatedly executed by the control unit 24 at a predetermined cycle, for example. In FIG. 5, processes corresponding to the processes shown in FIG. 3 are given the same reference numerals for the sake of convenience.

  In this series of processing, first, in step S30, it is determined whether or not an insulation failure is detected. Then, only when no insulation failure is detected, a process for determining whether or not the switching elements SW0 to SW4 are abnormal is performed in the manner shown in FIG. This is because when the insulation between the high voltage system and the vehicle body is poor, the voltage Va between the resistor 28 and the capacitor 38 is lower than the threshold voltage Vth regardless of whether the switching elements SW0 to SW4 are abnormal. Because it becomes.

  According to the present embodiment described above, the following effects can be obtained in addition to the above-described effects of the first embodiment.

  (5) Based on the presence or absence of detection of insulation failure, the presence or absence of abnormality of the switching elements SW0 to SW4 was determined. Thereby, it can avoid misjudging abnormality which originates in the insulation defect between a high voltage | pressure system and a vehicle body as abnormality of switching element SW0-SW4.

(Fourth embodiment)
Hereinafter, the fourth embodiment will be described with reference to the drawings with a focus on differences from the first embodiment.

  FIG. 6 shows the system configuration of this embodiment.

  As illustrated, in the present embodiment, short switches 40 and 42 that short-circuit each of the switching elements SSa and SSb and the voltage detection circuit 14 are provided. This is provided to electrically connect each of the switching elements SSa and SSb and the voltage detection circuit 14 to the vehicle body with a low impedance during the process of determining whether or not the switching elements SW0 to SW4 are abnormal. is there.

  FIG. 7 shows a procedure for determining whether there is an abnormality according to the present embodiment. This process is repeatedly executed by the control unit 24 at a predetermined cycle, for example. In FIG. 5, processes corresponding to the processes shown in FIG. 3 are given the same reference numerals for the sake of convenience.

  In this series of processing, instead of step S12 shown in FIG. 3 above, in step S12b, the short switches 40 and 42 are turned on together with the switching elements SSa and SSb being turned on.

  According to the present embodiment described above, the following effects can be obtained in addition to the above-described effects of the first embodiment.

  (6) The short switches 40 and 42 are turned on during the period in which the rectangular wave signal RS is output to determine whether or not the switching elements SW0 to SW4 are abnormal. As a result, the resistance values between the switching elements SSa and SSb and the voltage detection circuit 14 and the ground can be suitably reduced. As a result, the voltage Va between the resistor 28 and the capacitor 38 when the rectangular wave signal RS is output. Can be largely changed depending on whether or not the switching elements SW0 to SW4 are abnormal.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  The third and fourth embodiments may be changed by changing the second embodiment with respect to the first embodiment.

  -You may change the said 4th Embodiment by the change of 3rd Embodiment with respect to the said 1st Embodiment.

  In the first, third, and fourth embodiments, it is determined whether there is an abnormality in the high-voltage side switching elements SW0 to SW4 by turning on both of the low-voltage side switching elements SSa and SSb. Not limited to this, only one of them may be turned on. Accordingly, when it is determined that there is an abnormality, it is possible to narrow down the abnormal switching elements to those that can be connected to the switching elements that are turned on. That is, if it is determined that there is an abnormality when the switching element SSa is turned on, it may be determined that at least one of the switching elements SW0, SW3, SW4 that can be connected to the switching element SSa is abnormal. it can.

  In the second embodiment, all the high-voltage side switching elements SW0 to SW4 are turned on to determine whether the low-voltage side switching elements SSa and SSb are abnormal. However, the present invention is not limited to this. Only those that can be connected to either one of the switching elements SSa and SSb on the side may be turned on. Accordingly, when it is determined that there is an abnormality, it is possible to identify which switching element has the abnormality.

  The number of flying capacitors and voltage detection circuits is not limited to one, but may be plural. In this case, a battery cell to be detected may be appropriately assigned to each of the plurality of voltage detection circuits.

  In the third embodiment, when it is determined in advance that there is an insulation failure, the determination process for the presence / absence of abnormality of the switching elements SW0 to SW4 is not executed, but the present invention is not limited to this. For example, when it is determined that there is an abnormality in the switching elements SW0 to SW4 by the process illustrated in FIG. 3 as a temporary abnormality, and from this determination, it is determined that there is an insulation failure within a predetermined period. May cancel the temporary abnormality.

  The high-potential side connection means that can electrically connect the battery cell and the flying capacitor (power storage means) is not limited to the multiplexer MPX. For example, the same number of flying capacitors as the battery cells may be provided, and these may be electrically connected so that the voltage of each battery cell is detected by the corresponding flying capacitor. Even in this case, the application of the present invention is effective in determining whether there is an abnormality in the high-potential side connection means and the low-potential side connection means that connects each flying capacitor to the voltage detection circuit.

  -The AC signal is not limited to a rectangular wave signal. For example, it may be a sine wave signal. Thereby, it is possible to avoid the generation of high-order harmonics such as rectangular waves.

  In each of the above embodiments, the voltage detection target by the voltage detection circuit is the battery cell Bi, but is not limited thereto. For example, the voltage may be detected for each block composed of a plurality of battery cells adjacent to each other.

  -The battery cell is not limited to a lithium secondary battery. For example, a nickel metal hydride secondary battery may be used.

  -The assembled battery monitoring device is not limited to a device mounted on a hybrid vehicle, and may be a device mounted on an electric vehicle, for example. Furthermore, it is not restricted to what is mounted in a vehicle. Even in such a case, in order to determine whether there is an abnormality in the high-potential side connection means for connecting the unit battery and the capacitor or the low-potential side connection means for connecting the capacitor and the voltage detection means, the application of the present invention is applied. Is valid.

1 is a system configuration diagram according to a first embodiment. FIG. The figure which shows the abnormality detection principle of the switching element concerning the embodiment. The flowchart which shows the procedure of the judgment process of the presence or absence of abnormality of the switching element concerning the embodiment. The flowchart which shows the procedure of the judgment process of the presence or absence of abnormality of the switching element concerning 2nd Embodiment. The flowchart which shows the procedure of the judgment process of the presence or absence of abnormality of the switching element concerning 3rd Embodiment. The system block diagram concerning 4th Embodiment. The flowchart which shows the procedure of the judgment process of the presence or absence of abnormality of the switching element concerning the embodiment. The figure which shows the monitoring apparatus of the conventional assembled battery. The figure which shows the monitoring apparatus of the conventional assembled battery.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Battery pack, 12 ... Flying capacitor, 14 ... Voltage detection circuit, 24 ... Battery ECU (one embodiment of monitoring apparatus of battery pack), SW0-SW4 ... Switching element (one embodiment of high potential side connection means), SSa, SSb... Switching elements (one embodiment of low potential side connecting means).

Claims (6)

In order to detect the voltage of each unit battery composed of one or a plurality of adjacent battery cells constituting an assembled battery as a series connection body of battery cells, the unit battery and the power storage means are electrically connected by the high potential side connection means. After applying the voltage of the unit battery to the power storage means by connecting to the power storage means, the connection is released, and the unit battery is electrically connected between the power storage means and the voltage detection means by a low potential side connection means In the assembled battery monitoring device for detecting the voltage of
AC signal output means in which an output terminal is electrically connected to the assembled battery via a capacitor and a resistor;
Voltage between the resistor and the capacitor during a period in which an AC signal is output by the AC signal output means and the electrical connection is made by either the low potential side connection means or the high potential side connection means the basis, the monitoring of the assembled batteries, characterized in that it comprises a determination means for determining the presence or absence of any other abnormality of the low-potential-side connecting unit and the high-potential-side connecting means.   2. The assembled battery monitoring device according to claim 1, wherein the high potential side connecting means is a multiplexer that selects any one of the plurality of unit batteries and can be electrically connected to the power storage means. The electrical connection time for the determination process by the determination unit by either the low potential side connection unit or the high potential side connection unit is set as the electric power by the high potential side connection unit at the time of voltage detection of the unit battery. Further comprising setting means for setting longer than the typical connection time,
3. The assembled battery monitoring apparatus according to claim 1, wherein the determination unit performs the determination when the connection time is set by the setting unit. The assembled battery is mounted on a vehicle,
Based on the voltage between the resistor and the capacitor during a period in which an AC signal is output by the AC signal output unit and the electrical connection is not performed by any of the low potential side connection unit and the high potential side connection unit. The assembled battery monitoring device according to any one of claims 1 to 3, further comprising insulation failure detection means for detecting presence or absence of insulation failure between a high-voltage system including the assembled battery and a vehicle body.   5. The assembled battery monitoring apparatus according to claim 4, wherein the determination unit performs the determination based on whether or not the insulation failure is detected by the insulation failure detection unit. Further comprising a ground fault means for grounding between the low potential side connection means and the voltage detection means,
6. The determination unit according to claim 1, wherein the determination unit performs the determination when a ground fault is caused between the low-voltage side connection unit and the voltage detection unit. The assembled battery monitoring device described.

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